[PATCH] net/rds: Fix a use after free in rds_message_map_pages
From: Lv Yunlong <hidden>
Date: 2021-03-11 08:47:08
Also in:
linux-rdma, lkml
Subsystem:
networking [general], rds - reliable datagram sockets, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Allison Henderson, Linus Torvalds
In rds_message_map_pages, rds_message_put() will free rm. Maybe store the value of rm->data.op_sg ahead of rds_message_put() is better. Otherwise other threads could allocate the freed chunk and may change the value of rm->data.op_sg. Signed-off-by: Lv Yunlong <redacted> --- net/rds/message.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/rds/message.c b/net/rds/message.c
index 071a261fdaab..392e3a2f41a0 100644
--- a/net/rds/message.c
+++ b/net/rds/message.c@@ -347,8 +347,9 @@ struct rds_message *rds_message_map_pages(unsigned long *page_addrs, unsigned in rm->data.op_nents = DIV_ROUND_UP(total_len, PAGE_SIZE); rm->data.op_sg = rds_message_alloc_sgs(rm, num_sgs); if (IS_ERR(rm->data.op_sg)) { + struct scatterlist *tmp = rm->data.op_sg; rds_message_put(rm); - return ERR_CAST(rm->data.op_sg); + return ERR_CAST(tmp); } for (i = 0; i < rm->data.op_nents; ++i) {
--
2.25.1